Platform type weighing scales are commonly subject to nonuniform loading on the scale platform. It is difficult to provide a single platform support for a relative large scale platform that is capable of withstanding substantial nonuniform loading, and it has heretofore been proposed to make platform scales with four platform suspensions, with various different mechanisms for summing the loads applied to all four suspensions and for actuating a weight display. Some platform scales, for example as shown in U.S. Pat. No. 2,736,549, had two torque tubes extending between and interconnecting first and second pairs of the four platform suspensions and utilized two transfer levers connected through pivots to a weight indicating device. Some other platform scales, for example as shown in the U.S. Pat. No. 3,465,838, utilized four levers to transmit the loads on the four platform suspensions to a common load cell. However, the aforementioned platform scales utilizing two transfer levers or four transfer levers require substantial additional apparatus for mounting the weight indicating mechanism on the base and for applying forces from the several levers to the weight mechanism in order to actuate the later in accordance with the sum of the forces on the several levers.
It has also been proposed, for example as shown in U.S. Pat. No. 3,258,078 to provide load sensing devices such as strain gauges in each of the four platform suspensions and to electrically sum the signals from the four strain gauges on the four platform suspensions. However, even small differences in either the rate or linearity of response of the four strain gauges could cause variations in the indicated weight with different distribution of the load or weight on a scale platform. It is therefore necessary to carefully select and match the four strain gauges used in such scale for both linearity and rate of response in order to make a scale of this type which is relatively insensitive to nonuniform loading.